Improvement in auger-bit



uitrd gitarre @arent (twine.

Laws Patent No. 90,759, dated Jun@ 1, 1869.

IMPROVEMENT IN AUG-ER-BILI.

The Schedule referred to in these Letters Patent and making part of thesame.

To all ywhom it may conce/rn:

Be it known that I, H. G. LEWIS, of Essex, in the county v. of'Middlesex, and State of Connecticut, have invented a new Improvement inAuger-Bits; and I do hereby declare the following', when taken inconnection with the accompanying drawings, and the letters -of referencemarked thereon, to be a full, clear, and exact description of the saine,and which said drawings constitute part of this specification, andrepresent in- Fi/gure 1, an end view.;

Figure 2, a side view;

Figure 3, a side view, turned one-fourth around;

Figure 4, a section on line a: x; and in Figure 5, a section on line yy.

This invention relates to an improvement in that class ofboring-instruments known to the trade as auger-bits.

Heretofore, this class of bits has ,been formed by fitting the spur in aseparate piece, which often, by

hard use, breaks out from the body o f the bit, and' thus ruins theinstrument; and, further, these bits have been formed from a bar ofmetal, so thick that the chips' are all forced outward, and compelled tolI will proceed to a description thereof, as illustrated in theaccompanying drawings.

The bar from which the bit is to be formed is rst drawn dat upon theoutside, and convex upon -the inside, as seen in fig. 4, and so as toform a sharp edgey both above and below; the thickness of this bar beingonly so much as, when twisted, will leave an opening, A, through thecentre, as seen in fig. 5. This bar- I form about twice the width of theusual bar, that is to say, about equal to the space in the twist. anopening is formed entirely through the centre of the bit.

At the lower end the bar is turned down, and upon its centre is formed aconical screw, a, and from the screw outward a cutter, d, is formed,from the cutter falling back upon a gradual incline to the oppositeside, where the spur f is formed, and the incline continues beyond thespur until it dies out iu the twist, as seen in figs. l and 3. c

It is only necessary that the spur .be little longer, or project alittle below the cutting-edge; therefore, by inclining from the cutterto the spur, it requires but little more metal than is removed, informing this inclination to make the spur.

Thus, I have formed a most perfect single-twist A auger-bit; and havingthus fully .described my invention, I do not, broadly, claim placing thespur upon a single-twist bit, upon opposite sides to the cutter, as suchposition is common landrwell known; but, as before stated, when soarranged, the spur has been formed separate from and fitted into a seat,prepared at that point to receive it.

What I claim as new and useful, and desire to se- Thus,

